Jeremy Heywood rejected the idea that departments are punch drunk, and pointed to the Treasury, a bastion of stability. Photograph: John Stillwell/PA

At a recent private event cabinet secretary Sir Jeremy Heywood exuded sublime confidence in the civil service and Whitehall.

Crisis, what crisis, he said, rounding on critics and rejecting the idea that departments are punch drunk, reeling from the pummelling given them by ministers and topsy-turvy because of incessant changes in personnel at the top. Heywood pointed to the Treasury, a bastion of stability, where permanent secretary Sir Nicholas Macpherson has been in charge for ages and the chancellor is a happy customer.

Meanwhile, Cabinet Office minister Francis Maude is engaging in some odd behaviour. A few weeks ago, he dismissed calls from Bernard Jenkin, chair of the Commons public administration select committee for a root-and-branch examination of the civil service, led by parliamentarians, but he is now so upset by Whitehall's inability to do basic IT that has had to install his own Wi-Fi system in his office so he can use his iPad (which, given the security implications, sounds like a remarkable exercise in open government). Maude is also, without doing much to cover his tracks, briefing against permanent secretaries who allegedly are not up to scratch.

These two positions - serenity and criticism - can be reconciled once you understand and accept that central government is fractured and No 10's grasp is often strictly limited.

Where does this leave Whitehall mandarins? Heywood may be exultant because it's only a matter of time before the experiment in dual running at the top of Whitehall comes to an end and some face-saving exit is found for head of the civil service Sir Bob Kerslake, who surely deserves better than the bad mouthing recorded in Matthew D'Ancona's story of the Cameron coalition.

But the Devereux affair, which may sound like an episode from the court of Queen Elizabeth I, is a tale that lacks glamour and illustrates the thickets of complexity for Whitehall's highest officials.

In 2011, Robert Devereux moved from the Department for Transport to become permanent secretary at the Department for Work and Pensions. By then, the Universal Credit project was well under way.

Leaving aside Devereux's record at transport – a department not entirely covered in administrative glory in recent times – and his role as head of profession for policy, it is clear that at DWP he inherited a poisoned chalice. His has been a high profile job, including attempting to defend to MPs the record of contractors and the work programme. As far as Iain Duncan Smith is concerned, Devereux has been the man in charge - and he is perceived to have failed.

Of course, ministers under pressure tend to blame officials. But in previous governments,officials given impossible tasks could rely on the civil service machine, headed by the cabinet secretary, to look after their interests. Heywood's predecessors would, as necessary, intercede with the prime minister to defend beleaguered permanent secretaries against political attacks.

But it seems this is no longer happening. Instead, in this case, a whispering campaign has gone unchecked, leading to open speculation about how long Devereux can survive. The next piece of public criticism of universal credit could push him over the cliff.

That doesn't sound like everything in the Whitehall garden is lovely, whatever Pollyanna-Heywood may say.

David Walker is contributing editor on the Guardian Public Leaders Network

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